1. Field of the Invention
This invention relates to vacuum cleaners and, more particularly to a vacuum cleaner which is convertible from on-the-floor cleaning to above-the-floor cleaning. In another aspect, the invention relates to a conversion valve for converting an upright vacuum cleaner from on-the-floor to above-the-floor cleaning.
2. Description of the Related Art
Upright vacuum cleaners which are convertible from on-the-floor cleaning to above-the-floor cleaning are known in the prior art. Upright vacuum cleaners for on-the-floor cleaning typically have a brush roll housed in a chamber which is in fluid communication with the vacuum motor and open to the bottom surface of the foot. A wand or flexible hose on the foot or upright housing of an upright vacuum cleaner is fluidly connected to the vacuum motor to perform above-the-floor cleaning. A valve is typically used to control the source of suction generated by the vacuum motor between one of two suction openings, i.e., the brush roll chamber of the foot and the flexible hose. Examples of known upright vacuum cleaners of this type are disclosed in U.S. Pat. No. 5,351,361 to Buchtel; U.S. Pat. No. 5,222,276 to Glenn III; U.S. Pat. No. 4,376,322 to Lockhart et al; and U.S. Pat. No. 2,070,689 to Smellie. Another example of a vacuum cleaner having a valve for controlling air flow is U.S. Pat. No. 5,345,650 to Downham et al.
One problem with the prior art conversion valves for convertible upright vacuum cleaners is the automatic actuation of the conversion valve between on-the-floor cleaning and above-the-floor cleaning and vice-versa in response to the position of the upright handle between an upright position and a rearwardly tilted operating position. Several of the known conversion valves will automatically actuate a valve from the above-the-floor cleaning position to the on-the-floor cleaning position. However, most conversion valve systems of the prior art do not automatically actuate the valve to convert from on-the-floor cleaning to above-the-floor cleaning when the handle is returned to the upright position.
A second problem encountered in the conversion valve systems of the prior art is effectively sealing the air flow passageway to the closed suction opening so that essentially all of the air flow generated by the vacuum motor is directed to only the selected suction opening, i.e., the brush roll chamber or the flexible hose. An ineffective seal within the conversion valve will result in a reduction of the performance efficiency of the vacuum motor in generating lift in the selected suction opening.